Deflectors, part 2

Its Sunday. I made a matching rear deflector side-screen (iteration 4) for the passenger side.

Next step is to see how small I need to make to front deflectors. I looked at the picnic pictures and noted that Jeff & Julie’s deflectors are only about 4″ wide and go no higher than the top of the windscreen.

I also need to buy hinges and a pair of wing mirrors.

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Experiments with Wind Deflectors

I would like to drive the 7 without the side-screens (doors), but the wind turbulence is too much at speeds over 50mph. I’d seen some various deflectors at the 7’s picnic and wanted to try making one.

Iteration 1, front deflector

Iteration 1, front deflector

For a first iteration, I went with a larger size than the standard Caterham deflector (bigger is better?). This was made from 0.1″ acrylic (plexiglass) material. I had to borrow the hinges from the side-screen. I’ll have to buy some from the Caterham on-line shop.

I used some acrylic pieces that I had, but they were too small, so I had to extend by bolting on a 2nd piece. You’ll also notice a bend, this is achieved by heating the acrylic with a propane torch, very slowly and moving constantly, until the acrylic is soft enough to bend. If you get it too hot it will bubble or even catch fire. I found that it is easy to go too far and most of my bends do not look attractive (as you will see). The soft acrylic is also susceptable to thumb & finger glove prints (you have to wear gloves as it’s really hot).

Iteration 2

Iteration 2

I went for a test drive, it was better than nothing, but still a lot of buffeting.  I thought I needed some modification, so went back home and made some bends to make the top of the deflector more streamlined with less drag. This gave me iteration 2.

Another test drive and I did not see any real improvement. What I did notice however was that wind was coming in at head level at the side of my head and blowing my hair forwards. Lacking a wind tunnel, I used my hand as a tell-tale and moved to various positions just outside the car as I was driving to determine where the wind was coming from. It appears that wind is moving along the side of the car until it reaches the rear wheel & wing (fender), then it is forced upwards. I went back home and to the drawing board.

I did draw a picture. What I think is happening is first, wind is pushed upwards and back over the front windscreen. This creates a partial vacuum inside the driver’s cockpit. Wind from the side, moving upwards around the rear wing is then sucked into the partial vacuum of the driver’s cockpit. See below picture, blue ink arrows show the wind from the side.

OLYMPUS DIGITAL CAMERA

Iteration 3, rear side screen.

Iteration 3, rear side screen.

If my hypothesis is correct, I need a partial side screen at the rear of the cockpit. So I set about making one. This would be iteration 3, see picture. I managed to use 2 of the poppers to hold the screen in place in addition to a zip-tie to the roll bar, with a piece of polystyrene foam.

Time for another test drive. Much better, I can drive at 70mph with less buffeting than at 50mph without deflectors. I’m on the right track.

Iteration 3. Broken acrylic.

Iteration 3. Broken acrylic.

 

 

 

 

 

Before going home, I filled up with gas and promptly broke the acrylic side-screen. I guess it was rather too delicate, made of 0.1″ acrylic sheet. I had suspected that 0.1″ was too thin and had bought a piece of 0.22″ acrylic sheet – it was $50, so I have been trying the 0.1″ thick prototypes first.

Back home, and I set to work on iteration 4. This time made out of 0.22″ acrylic. Note that I’m cutting the acrylic sheet with a bandsaw, scoring 0.22″ acrylic and snapping does not work. It’s also harder to make the bends as the whole 0.22″ has to be heated throughout before a bend will happen.

Iteration 4, view 1.

Iteration 4, view 1.

Iteration 4, view 2.

Iteration 4, view 2.

___________________In the iteration 4, you will note a curve outwards. This is to accommodate my shoulder. There is a bend at the back to follow the roll bar contour. There is also a ~15degree bend just below the lower popper so that the bottom follows the side of the car.

Test drive time, up to 80mph, there is some marginal buffeting and my hair flies around, but I’m driving with open sides!

Front and rear deflectors.

Front and rear deflectors.

Fitted deflectors

Fitted deflectors

Headlight wiring

 

Small exit hole shown in the mirror

Small exit hole shown in the mirror

At Saturday’s picnic, Mark remarked that the wiring to the headlight is not supposed to be dangling, but fed through the hole in the tubular headlight mount.

So, on returning home, after removing the bonnet (hood) and nose, I set about fixing it. At first I thought I could simply thread the wire through but was thwarted by the small hole on the outlet side. You can just about see it on the mirror in the picture……..

So, I had to remove the headlamp brackets, by first undoing the anti-roll/sway bar mounting brackets on either side, the removing the top front control arm bolt, which then releases the headlight mounting brackets.

Feeding the wires

Feeding the wires

Removed the pins from the headlight plug and cut short the exterior sleeving, leaving just enough to cover the wires as they transition from the bottom of the lamp to the hole in the mounting bracket. There was a grommet in the end of the mounting bracket tube that had to be removed and then put back after all the wires were in place.

Thread the wire through the car-side mounting point, then bolt the bracket in place with the control arm bolt. Put back the anti-roll bar bolts & torque all the bolts.

Put the pins back into the plugs and plug in.Turn on the light switch and the lights came on. Job done. When completed, it does look better.

Wire threading completed and sleeve installed.

Wire threading completed and sleeve installed.

Completed.

Completed.

7’s Picnic

The annual California Caterham Club picnic was held at Vasona Park in Los Gatos. This year 17 cars attended, several Caterhams, a Lotus, a Westfied, a Birkin and 2 WCMs. Following are the pictures……and some video links, with the drive map at the end.

Leaving home with the 7 on a trailer.

Leaving home with the 7 on a trailer.

That 7 is mighty close in the rear view mirror

That 7 is mighty close in the rear view mirror

Pit stop at Gold Run

Pit stop at Gold Run

The 7 line up before the drive

The 7 line up before the drive

Panoramic view of all the cars with Sarah & Dave in foreground

Panoramic view of all the cars with Sarah & Dave in foreground

Adam,Dave & Julie

Adam,Dave & Julie

Adam, Dave & Dot

Adam, Dave & Dot

Larry, Goya & Doug's wife

Larry, Goya & Doug’s wife

Grid line up, ready for the drive

Grid line up, ready for the drive

Dot, sitting on the grid

Dot, sitting on the grid

Rear view

Rear view

We found this Frog Eye at the cafe on Skyline Boulevard

We found this Frog Eye at Alice’s Restaurant on Skyline Boulevard

Also this Morgan +4

Also this Morgan +4

On returning, we discovered Dave Lowe's car on a AAA trick, he had only managed about 1 mile before the engine died. Suspected head gasket.

On returning, we discovered Dave Lowe’s car on a AAA trick, he had only managed about 1 mile before the engine died. Suspected head gasket.

This was half the gang

This was half the gang

Left to right: (omitting the non 7’s)Doug Lowe’s, Larry & Goya’s Birkin, Raul’s WCM, Jeff & Julie Hamlin’s Lucy Cate; GWise’s red Lotus 7.

and the other half making 17 total

and the other half making 17 total

Left to right (back): Jeff &Julie Hamlin’s Lucy Cate; GWise’s red Lotus 7; Jim’s blue WCM; Russ, Andreas, Mark & Sarah Pierpoint’s CSR 175, my 7.

Left to right (front):  Sean’s; the Westfield; green 7; Adam’s CSR260; John’s green 7 with yellow nose & gull  wings; CASweede Don’s green 7 with yellow stripe & gull wings; Mopho’s yellow 7

Car inspections going on

Car inspections going on

Mark's limited soft top from "Softbits for sevens"

Mark’s limited soft top from “Softbits for sevens”

Close up of the top

Close up of the top

Julie's short top has a zipper

Julie’s short top has a zipper

Wind deflector & mirror on Lucy Cate(Jeff & Julie's 7)

Wind deflector & mirror on Lucy Cate(Jeff & Julie’s 7)

This is Sean's engine, Duratec, Cosworth and ~260bhp

This is Sean’s engine, Duratec, Cosworth and ~260bhp

Mark's engine in his CSR with Euro style exhaust

Mark’s engine in his CSR with Euro style exhaust

Sean's inboard suspension

Sean’s inboard suspension

Mark, Sarah, Sean & Lorraine

Mark, Sarah, Sean & Lorraine

Lorraine, Steve, Andreas & Dave (with eye's closed)

Lorraine, Steve, Andreas & Dave (with eye’s closed)

 

 

Heading home the following morning

Heading home the following morning

Here’s a link to Mopho’s video: http://vimeo.com/103043966
Here’s a link to Julie’s video: http://vimeo.com/103079152

Here is the drive route……